1. Field of the Invention
This invention relates to an improvement in a blank for making a container or envelope and in one aspect relates to an improved closing and opening system for containers such as envelopes.
2. Description of the Prior Art
The commercially available envelopes for mailing and for overnight delivery parcels have adhesive closure systems and many have tear strips for facile opening. One such opening system is illustrated in U.S. Pat. No. 4,781,296 for use on envelopes of tough non-woven thermoplastic fibers. Another easy open strip is shown in U.S. Pat. No. 4,778,059 showing a tear strip for use on a corrugated shipping carton. Similarly, U.S. Pat. No. 5,098,757, available from the assignee of this patent (application) illustrates a further structure for a tear strip for a corrugated package or carton. This later patent discloses a hot melt coated tear tape adhered to the outside surface of the inside liner along the desired line of opening and a hot melt coated tear guide tape, at least as wide as the tear tape, adhered to the inside surface of the outside liner. The two adhesives are separate and do not join one another but both serve to provide the desired even tear line.
U.S. Pat. No. 4,877,139 discloses a container having an opening-closing flap provided with a strip of adhesive disposed along a straight line on the inside surface of the flap for sealing the container, and a non-tearable guide strip disposed along the outside surface and a non-tearable elongate straight tear band attached to the inside surface of the flap along a perforated punch line to allow the opening with one edge of the tear band aligned with an edge of the guide strip so that when the flap is sealed by the adhesive and the tear band is freed and pulled away from the container, the container is opened with a tear line which extends along the container flap in a straight line.
The present invention affords a single adhesive strip on the closing-opening flap to seal the container closed and to provide a facile tear strip to open the flap and container once it is sealed.
The present invention further has the advantage that the manufacturer of the container or envelope has only one tape or ribbon to inventory. Only one tape to guide and apply during manufacture of the envelopes. And, only one piece of tape applicating equipment on the line.